Grapefruit—cut in half and served fresh, or consumed as juice—can be a good source of vitamin C. However, the fruit can interact negatively with some over-the-counter remedies and some prescription medications, including some statin drugs used to lower cholesterol and some drugs prescribed to lower blood pressure.

As with most drugs that interact unfavorably with it, grapefruit increases absorption of the drug into the bloodstream and can create the potential for toxic buildup, according to a news release posted by the U.S. Food and Drug Administration (FDA). For years, the FDA has required some prescription medications to carry warning labels about consuming grapefruit while taking these drugs.

Now, based on ongoing research, the agency is expanding its warnings about potential drug interactions with grapefruit juice and other fruits. Shiew Mei Huang, an acting director at the FDA, says in the news release that some studies done more recently have found the juice also can reduce -rather than increase - absorption of certain drugs.

For example, Huang says, grapefruit juice reduces the absorption of fexofenadine (brand name Allegra), used to help allay symptoms of seasonal allergies. This can lessen its effectiveness. The drug also can be less effective when interacting with orange or apple juice, so its label now says, "Do not take with fruit juices."

The FDA suggests consumers ask a pharmacist, doctor, or other health care professional if it is safe to consume grapefruit or other fruits with their medications. Also, carefully read the Medication Guide or patient information sheet provided with prescription medications and check for fruit warnings. When taking an over-the-counter drug, check the Drug Facts label.

For more information, visit www.fda.gov and search for "Avoiding Drug Interactions."

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